A prospective cohort study on human immunodeficiency virus and syphilis seroconversion among injecting drug users / 中华流行病学杂志

<p><b>OBJECTIVE</b>To study the rate of human immunodeficiency virus (HIV) seroconversion, HIV transmission and related risk factors among injecting drug users (IDUs) in an area of Sichuan province.</p><p><b>METHODS</b>In November 2002, a community-based baseline survey was conducted to recruit 333 HIV-seronegative IDUs for a prospective cohort study in Xichang county of Sichuan province, China. Follow-up visits were carried out every 6 months to study the situation of drug use, sexual behaviors of the IDUs and blood specimens were collected to test for antibodies against HIV and syphilis.</p><p><b>RESULTS</b>During a 24-month follow-up period, cohort retention rate and HIV incidence were 75.7% and 2.53 per 100 person-years [95% confidence interval (CI): 1.10-3.97)], respectively. Multivariate Poisson regression model showed that risk factors which were significantly associated with HIV seroconversion would include: ethnicity (RR = 12.42; 95% CI: 2.72-56.74, P = 0.0012) and needle or syringe sharing in the past 3 months (RR = 4.06; 95% CI: 1.29-12.81, P = 0.0168). Syphilis seroconversion in this cohort was 4.71 per 100 person-years (95% CI: 2.59-6.82). In multivariate Poisson regression being female (RR = 4.42; 95% CI: 1.78-10.99, P = 0.0014) appeared to be the only factor which was significantly associated with syphilis seroconversion.</p><p><b>CONCLUSION</b>Our study results showed that there was a rapid transmission of HIV and syphilis among IDUs in Sichuan province, suggesting that effective intervention should be urgently taken.</p>

An 1-year prospective cohort study on mortality of injecting drug users / 中华流行病学杂志

<p><b>OBJECTIVE</b>To study the mortality among injecting drug users (IDUs) from an IDUs cohort in Liangshan of Sichuan province.</p><p><b>METHODS</b>In November 2002, 376 injecting drug users were recruited and followed up for 1 year as part of a prospective cohort study. Socio-demographics and risk behaviors on drug use were recorded. After one year, the mortality rate was estimated and risk factors for mortality were analyzed using Cox regression.</p><p><b>RESULTS</b>Out of the original cohort of 376 participants, there were 28 reported and confirmed deaths during the one year follow-up period. The mortality rate of the cohort was 77.32 per 1000 person-years (95% CI: 48.68 - 105.95) with the standardized mortality ratio (SMR) as 47.62 (95% CI: 31.63 - 68.71). Out of the 28 deaths, 64.3% (18/28) caused by overdoses of drug. No variables were found to be associated with death of all causes, but being un-married and >or= 9 year history of injecting drugs were found to be associated with overdose-related mortality in the final model of Cox regression. The hazard ratios were 4.51 (95% CI: 1.03 - 19.67) and 2.77 (95% CI: 1.10 - 7.00) respectively.</p><p><b>CONCLUSION</b>Overdose served the most frequent cause of deaths in Liangshan of Sichuan province. Future studies should be conducted to focus on mortality and risk factors associated with mortality among IDUs to provide targeted interventions in reducing unnatural mortality.</p>

Community-based survey on human immunodeficiency virus infection among injection drug users in Sichuan, China / 中华预防医学杂志

<p><b>OBJECTIVE</b>To investigate prevalence of human immunodeficiency virus (HIV) infection and risk factors for its transmission among injection drug users (IDUs) in Liangshan Yizu Autonomous Prefecture of Sichuan Province, China.</p><p><b>METHODS</b>A community-based survey was conducted to investigate demographic characteristics, pattern and frequency of sharing injection equipment, and sexual behaviors in IDUs. Blood samples were also collected from them to detect for antibodies against HIV and syphilis.</p><p><b>RESULTS</b>A total of 379 subjects were recruited with informed consent for study through community outreach and peer recruiting methods. Their prevalence of HIV infection was 11.3% (43/379). Ethnicity, frequency of sharing syringes and cotton swab during the past three months and syphilis infection associated with HIV infection by univariate analysis using chi-square test. Multivariate logistic regression analysis showed odds ratio of frequency of sharing syringes for HIV infection during the past three months was 2.28 (95% CI 1.18 - 4.43), and that for syphilis infection 3.10 (95% CI 1.48 - 6.48).</p><p><b>CONCLUSION</b>Frequency of sharing syringes during the past three months associated with syphilis and HIV infection.</p>

Study on the relationship between hepatitis C virus infection and sharing injection equipment, sexual behavior among injecting drug users / 中华流行病学杂志

<p><b>OBJECTIVE</b>To study hepatitis C virus (HCV) transmission through different modes of sharing injection equipment and sexual behavior among injecting drug users (IDUs) in Liangshan of Sichuan province.</p><p><b>METHODS</b>A community-based survey was conducted to investigate past and current demographic data, injection equipment sharing patterns and sexual behavior of IDUs. Blood samples were also taken to test for HCV. The survey was conducted between Nov 8 and Nov 29, 2002. 379 subjects were screened through outreach recruitment and peer informing. SPSS (11.5) was used for data analysis.</p><p><b>RESULTS</b>HCV prevalence was 71.0% (269/379). Needles or syringes sharing in the past three months and past syphilis infection were strongly associated with HCV transmission after univariate analysis using chi-square test. Trend analysis indicated that HCV infection rate increased along with the increase of needles or syringes sharing, sharing of rinse water and the number of peers sharing the equipments. Data from multivariate logistic regression showed that sharing of needles or syringes and history of syphilis infection were significantly associated with HCV transmission. No significant difference was found between HCV infection and sexual behavior after univariate analysis using chi-square test.</p><p><b>CONCLUSION</b>Further sero-epidemiological prospective cohort studies should be conducted to clarify the relationship between different modes of sharing injection equipment, sexual behavior and HCV infection.</p>